This invention is in the field of union connectors for releasably coupling the ends of two pipes and of a combination of a union connector and a truss mount which is releasably connectable to a truss, such union connectors being commonly used to support lighting fixtures from overhead horizontal trusses or from vertical trusses.
Truss union connectors, particularly in combination with truss mounts, are used commonly to support lighting fixtures used in trade shows, theaters, clubs or other environments. In many of these situations time is critically important as during installation or assembly and disassembly when sets are changed during a theatre production or where displays are set up or removed at trade shows.
Often at theater and trade show sites there is shortage of tools during the set-up or change-over transitions. Thus, it is desired to have the simplest connector structures which are quick and easy to use, and reliable. Some prior art structures focus primarily on accuracy or positioning and security of attachment, and unfortunately produce structures that are complex in terms of components and manufacture and either difficult and/or time-consuming to use. Typically, in prior art structures, achievement of one objective often dictates failure of another. For example, many prior art structures utilize bolts as the basic fastening elements which usually extend transversely and completely through a pipe perpendicular to its axis, as seen in U.S. Pat. No. 6,030,142, U.S. Pat. No. 5,184,911, U.S. Pat. No. 4,901,970, U.S. Pat. No. 5,609,436, and U.S. Pat. No. 5,536,102. While these prior art patents are primarily for coupling a pipe to another structure as opposed to coupling two pipes in end-to-end orientation, and while they may allege to be simple and easy to use and suitable for rapid installation, each disclosure has either multiple parts or a design which not suitable for easy and quick use in an awkward overhead position. As indicated above, bolts and pins in prior art devices invariably extend fully through the connected elements, thus necessitating more time and dexterity to assure proper orientation of components and full engagement and subsequent disengagement. This is both frustrating and costly where assembly or disassembly takes extensive time while subsequent phases must wait.
The relevant prior art concerns not only truss union connectors for removable attachment of pipe extension components of lighting fixtures and the like to existing pipe elements, but also to truss mounts for removable attachment of these truss union connectors to trusses which include common ladder type and triangular type trusses and other related structures.
This invention is a connector for releasably coupling the ends of two axially aligned pipes, where the connector has simple construction and is operable easily and quickly by actuating a simple knob. This connector is optionally combined with a truss mount where one of the coupled pipes is mounted to a truss. The new connector includes a set of split cylinder shell segments that engage the outer surfaces of the ends of the coupled pipes. These shells engage the pipes easily, quickly and securely primarily by use of short dimples that extend from the bore surface of the split cylinder shell segments radially inward into holes in the walls of the pipes. Numerous variations of this coupling concept are possible such as dimples extending radially outward from the pipes into holes in the shell segments. For convenience of manufacture the holes may extend completely through the pipe or shell wall respectively, or the holes may be replaced with shallow recesses or grooves in the surface receiving the dimples or other projections.
It is an object of this invention to provide a coupling which is simple to manufacture and to operate, and which can be assembled and disassembled very quickly and easily even in overhead or other awkward positions.
It is a further object to have a coupling assembly which is integrated such that its components will not fall apart while the unit is being used to join pipes. In one embodiment the coupling assembly is fixed in part to a first pipe end and adaptable to receive and releasably engage the end of another pipe. Such assembly is readily operable to receive the second pipe and easily closable into a secure coupling while the components are not able to fall apart or become mis-oriented. In one preferred embodiment the coupled pipes are coaxial and of the same diameter; however, in other embodiments the pipes may be non-coaxial and of different diameters.
A still further object is to combine this coupling assembly with a truss mount which is releasably connectable to a ladder truss, triangular truss or other structure and simultaneously serves to couple ends of two aligned pipes.
An additional object is for the assembly to be operable by rotation of a single thumbscrew. In one embodiment the thumbscrew, when initially turned, rotates the thumbscrew shaft into a distal nut where the shaft locks; further rotation of the thumbscrew causes the thumbscrew to move axially on the shaft and drive the shells tightly against the coupled pipes.
A further embodiment utilizes a set of split cylinders or shells which when assembled into a connector define a split cylinder separated by a central axial plane. The shells when assembled define an outer cylinder concentric about the adjacent ends of the end-to-end pipes, and each shell overlies said opposing pipe ends. These pipe ends are slightly spaced apart, and a bolt fastener extends transversely through and engages said two shells and extends between the terminal ends of said adjacent but spaced apart pipe ends. To retain said pipe ends from moving axially away from each other, each pipe end has at least one set of holes extending radially inward and situated axially inward from its terminal end, and each shell has extending from its base surface two axially spaced dimples extending radially inward. In use one shell has one dimple extending through the radial hole of one pipe and the other dimple extending through the radial hole of the other pipe, these transverse projections from the shells into the pipes serving to bar axial displacement of the pipes relative to each other. The second shell has two generally similar inward projections except that one is a dimple for releasably coupling to one pipe and the other projection is a bolt or rivet permanently securing the shell to the end of one pipe. The transverse central bolt, preferably has at its top end a socket head drivable by an Allen wrench with external threads for cooperation with a wing nut, and at its bottom end threads to engage a nut or other threaded receptacle.